A complex of p190RhoGAP and anillin modulates RhoGTP and the cytokinetic furrow in human cells

Abstract

The cytokinetic furrow (CF) is organized by the RhoA GTPase, which recruits actin and myosin II to the furrow and drives contractility. Here we show a role for the RhoGAP, p190, in cytokinesis and its involvement in regulating Rho GTP levels and contractility. Cells depleted of p190RhoGAP (p190) accumulate high levels of RhoGTP and markers of high Rho activity in the furrow, resulting in failure of the CF to progress to abscission. The loss of p190 can be rescued by a low dose of the myosin II inhibitor blebbistatin, suggesting that cells fail cytokinesis because they have too much myosin activity. p190RhoGAP binds the cytokinetic organizer anillin, and mutants of p190 that are unable to bind anillin or unable to inactivate Rho fail to rescue cytokinesis defects in p190-depleted cells. Together these data demonstrate that a complex of p190RhoGAP and anillin modulates RhoGTP levels in the CF to ensure robust cytokinesis.